1. Revelation of Neural Gene Functions using Transgenic and Knockout Mice ApproachFunctional characterization of novel neural genes and those previously uncovered in CNS areas implicated in cognition are currently underinvestigation both in vitro and in vivo. The candidate genes are 2 adrenoceptor subtype genes Adra2b and Adra2c encoding a2B and a2C adrenoceptor respectively. a2 adrenoceptor subtypes mediate the specific effect of norepinephrine via G protein-coupled signal transduction pathways in selected areas in CNS. Luzp is the gene encoding a putative transcription factor LUZP predominantly expressed in brain areas such as temporal cortex, hippocampus and cerebellum. Promoter-reporter transgenic mouse lines of both a2B and a2C adrenoceptor have been established in which cis-elements-reporter constructs linking lacZ were used to trace the temporal and spatial expression of specific receptor subtypes as directed by different domains of regulatory region of its gene. These models were employed to facilitate the study of receptor expression regulation. We have also established 3 lines of knock-out mouse models in which the candidate genes; Adra2b, Adra2c and Luzp, were each targeted disrupted and a reporter gene lacZ was in-frame inserted downstream to the regulatory region of respective genes. The adrenoceptor subtype deficient mutants provide in vivo models in which their respective expression atlas in brain may be established and their functional significance in emotion regulation (e.g., aggression and addictive behaviors) may be explored. The LUZP-null mice are currently employed to delineate its role in neural tube closure in embryonic brain. The selective expression of LUZP in hippocampus prompted the use of heterozygous Luzp-mutant to delineate its role in stress response by pharmacogenetic approach. Condition knockout mouse lines will be established employing the Tet-on system and specific promoter driven Cre-loxP recombinase system. The mutant mice with definitive molecular lesion are excellent in vivo models in which the functional involvement of each candidate gene at the cellular, system, behavioral and cognitive levels may be assessed.

2. Immortalization and Characterization of Neural Cell LinesThe myelin deficient (msd) rat is a model system for human demyelinating diseases. The mutant is characterized by defective oligodendrocytes, the central myelin synthesizing glia. We have established and characterized a clonal oligodendrocyte line CBII. Further characterization in terms of its functional competence; the capacity to make myelin both in vitro and in vivo systems are under pursue. In addition, we have established a murine neuronal cell line DM, derived from embryonic (E13) mesencephalon and used it as an in vitro model system for mesolimbic dopaminergic neurons. We are in the process of characterizing its apoptotic response to addictive drugs such that neural protective strategies may be devised.